<h3>1.描述</h3>
<p>activeClass接口测试（此接口是否多余）</p>
<h3>2.示例</h3>
<p>(2.1)单选按钮组测试</p>
<ti-button-group
  [items]="items"
  id="buttongroup"
  [(ngModel)]="selected"
  [activeClass]="activeClass"
  (ngModelChange)="radioChangeFn($event)"
>
</ti-button-group>
<p>选中项：{{selected | json}}</p>
